code: def read_metadata(self):
      offset = HeaderType.itemsize + self.field_descriptors.nbytes
      self.metadata = np.fromfile(
          self._fname,
          dtype=self.metadata_type,
          count=self.num_samples,
          offset=offset,
      )
      self.metadata.setflags(write=False)
  
file_path: ffcv/ffcv/reader.py
imports: import numpy
  from .utils import decode_null_terminated_string
  from .types import ALLOC_TABLE_TYPE, HeaderType, CURRENT_VERSION, FieldDescType, get_handlers, get_metadata_type
label_desc: Use image node_id 5 for calling the Reader obj's underlying member method code with example usage: obj.read_metadata() without return types